Radio host Scott Simon never intended to tweet his mother's final hours to 1.2 million followers, but her dying moments were among the most emotional in his public life.

"I have covered 10 wars and been around the world," Simon told ABCNews.com. "But I am telling you, the 48 hours we stayed up together was one of the most exhilarating in my life. And she was also, for the benefit of her family, giving a really great performance, and no less sincere, rallying herself to be strong to relieve our anxieties."

His tweets -- beginning July 16 when he learned about her emergency surgery to her death July 29 -- resonated around the world and drew praise from those who had similarly experienced the death of a loved one.

From the ICU at Northwestern University Memorial Hospital, he tweeted until the "Heart rate dropping. Heart dropping" moment, sharing his 140-character view of life's final journey.

Simon, 61, told ABCNews.com that he hadn't intended to tweet about his mother's death during the many monotonous moments in the ICU.

"I didn't expect it to be my mother's death bed," he said through tears. "It wasn't my frame of mind. I felt it could be the end, but I had one big reason to fight like a lion for her. ...I am her son and we were going to beat this together.

"I don't want people thinking I was holding my mother in my arms and tweeting. [As in] war, there are often seconds of panic and anxiety and terror between hours of tedium."

As Simon put it so emotionally over Twitter: "The heavens over Chicago have opened up and Patricia Lyons Simon Newman has stepped on stage."

"It's not that he should or shouldn't do it; that's for him to decide and discuss with his mom and other relatives," he said. "But it's clear to me that one of the last places -- sex, birthing and dying -- are not off limits anymore. There aren't many spheres left, and that's a really notable shift."

Simon said his mother may not have understood what Twitter was, but she told her son after learning of the millions around the world who had tweeted him in support, "How very nice of them."

He said he was not grieving until the end. "Not only had we kept hoping, we did until her last breath," he said.

Simon
described holding his mother's hand: "Haven't held it like this since I was 9." And shares her pain: "Will this go on forever?"

He jokes about one of the "great little things in life" is flossing her teeth. Then he tears up when his mother reacts to the birth of the royal baby.

"She had so many flabbergastingly insightful and funny things to say: 'Look baby, I tell you all great death-bed speeches are written in advance.' She was hilarious."

Newman had been a model -- the Jon James hair spray girl -- and did television commericals. Simon said he got his own in the public eye appearing with her in an advertisement for Archway cookies when he was about 8.

"She had lied about her age to work nightclubs to work at 16," he said. "My dad, Ernie Simon, was a comedian."

And one of the last goodbyes: "Mother cries Help Me at 2:30. Been holding her like a baby since. She's asleep now. All I can do is hold on to her."

Simon also tweets about the difficulty of delivering the sad news to his daughters Elise, 10, and Lina, 6:
"Worst: telling our daughters. Oldest was flinty, youngest sobbed."

Meanwhile, Simon's heartfelt messages have gone viral, encouraging strangers to respond and share in his grief.

One follower, Steve McLaughlin, tweeted, "I haven't held my mother's hand in a long time, thank you for reminding me that time is fleeting and that I need to do that."

Other public figures have shared similar moments, but not in real time on the Internet. In 2004, the photographer Annie Leibovitz documented the death of her partner, writer Susan Sontag. Her son later called the photos, "carnival images of celebrity death."

"Social media has changed the way many people do lots of things," said Dr. Stuart Youngner, the Bioethics Department chairman at Case Western Reserve University School of Medicine in Cleveland. "Why not grieving? Scott Simon is a public figure and may well find that pubic expression of what many consider private feelings is helpful to him."

"After all," he adds. "Eric Clapton wrote a song about his young son who fell and died from an open window."

Philadelphia psychologist Ann Rosen Spector agrees that social media are "just a fact of life now."

But when it comes to grieving, sharing can be helpful, "as long as people don't feel pressured into doing it," she said. "Some people share every time they buy a new pair of shoes or sneeze or cough. Some people share medical updates. It's a whole new world. There is not a standard of care to grieve."

Kenneth Doka, a senior consultant to the Hospice Foundation of America and author of "Beyond Kubler-Ross: New Perspectives on Death, Dying and Grief," calls the support system that Twitter created around Simon "an incredible phenomenon."

But he said he was "curious" why Simon's mother was in so much pain, given scientific and medical advances in hospice care. "I wondered if we did all we could for this woman in pain," said Doka, who's also a professor of gerontology at the Graduate School of The College of New Rochelle in New York.

Simon said his mother had received morphine for her pain in the end. "Those people were ICU heroes," he said. "I am grateful to them and my family owes then a permanent debt."

"One of the most profound comments I read was how he held his mother's hand so tightly," Doka said of Simon. "Don't wait until the end to say, 'I love you.' That is an awesome life lesson."

Although Twitter is a modern mode of communication, societies over the centuries have had their own tools, Doka said.

"When you look at the pyramids, we have always reached out to death and dying and this is our most current technology, our monument," he said.

But NYU's ethicist Caplan still worries about the ethics of informed consent and who gives permission to make private moments public?

"[Simon] is a very savvy media person who understands privacy and confidentiality issues and has decided, for whatever reason, that it is helpful to him and might be beneficial to others," he said.

Caplan recommends families discuss these issues with their loved ones before the time of death. Or at least include a mention in advanced directives or living wills.

"It's good to have an opportunity to talk about it," Caplan said. "One hundred years ago, you would be present at the death of a loved one, but now, it's not as common. People die in hospitals.

"Sharing some of that is important," he said. "Society finds it very difficult to talk about death and dying. But it would be better if we could get people to talk about it before and not in the middle of it."

As for Simon, who is was still in Chicago, visiting the cemetery to make plans for his mother's interment, he said, "We are OK. Talking so much about my mother and being surrounded by her things in her apartment, I have this most distracting sense that she is still with us."